I incubated 18 Cuckoo Marans eggs once in my Turn-X 7 forced air 10-turn incubator. There were 12 that hatched. Of the 6 that didn't make it, 2 in particular were strange. The fully developed embryo had turned completely backwards, head at small end, its butt at the air sac. The chick had drowned in its own fluid. Again, fully developed. All eggs were positioned with the large end tilted up, pointy end down (well, actually if you're familiar with TX-7s the eggs lay on their side. I've been hatching eggs for 36 years, small scale, no fancy cabinet incubators here (I wish I had one!). Has anyone else ever seen this? Last year is the first time I had seen this in 35 years. I've hatched OE bantams whose air sac was so big (humidity set too low) that the chick pipped THROUGH the shell near the small end, but the chick was healthy as a horse after hatching.